#ifndef __LOG_HPP__
#define __LOG_HPP__

#include <iostream>
#include <cstdio>
#include <string>
#include <filesystem> //C++17 std::filesystem::exists(_path)
#include <sstream>
#include <fstream>
#include <memory>
#include <ctime>
#include <unistd.h>
#include "Mutex.hpp"

namespace LogModule
{
    using namespace MutexModule;

    const std::string gsep = "\r\n";

    class LogStrategy
    {
    public:
        ~LogStrategy() = default;
        virtual void SyncLog(const std::string &message) = 0; // 纯虚函数：继承子类必须实现
    };

    // 显示器打印日志的策略
    class ConsoleLogStrategy : public LogStrategy
    {
    public:
        ConsoleLogStrategy() {}
        void SyncLog(const std::string &message) override
        {
            LockGuard lockguard(_mutex);
            std::cout << message << gsep;
        }
        ~ConsoleLogStrategy() {}
    private:
        Mutex _mutex;
    };

    //文件打印日志的策略
    const std::string defaultpath = "/var/log/";
    const std::string defaultfile = "my.log";
    class FileLogStrategy : public LogStrategy
    {
    public:
        FileLogStrategy(const std::string &path = defaultpath, const std::string &file = defaultfile)
            :_path(path) ,_file(file)
        {
            LockGuard lockguard(_mutex);
            if (std::filesystem::exists(_path)) // 判断文件或目录是否存在
            {
                return;
            }
            try
            {
                std::filesystem::create_directories(_path); // 尝试创建一个目录
            }
            catch (const std::filesystem::filesystem_error &e)
            {
                std::cerr << e.what() << std::endl;
            }
        }
        void SyncLog(const std::string &message) override
        {
            LockGuard lockguard(_mutex);

            std::string filename = _path + (_path.back() == '/' ? "" : "/") + _file; // 检查格式
            std::ofstream out(filename, std::ios::app); // 打开filename文件，app为追加模式
            if (!out.is_open())
            {
                return;
            }
            out << message << gsep;
            out.close();
        }
        ~FileLogStrategy()
        {}
    private:
        std::string _path;
        std::string _file;
        Mutex _mutex;
    };

    enum class LogLevel // 枚举日志等级
    {
        DEBUG,
        INFO,
        WARNING,
        ERROR,
        FATAL
    };
    std::string Level2Str(LogLevel level)
    {
        switch (level)
        {
        case LogLevel::DEBUG:
            return "DEBUG";
        case LogLevel::INFO:
            return "INFO";
        case LogLevel::WARNING:
            return "WARNING";
        case LogLevel::ERROR:
            return "ERROR";
        case LogLevel::FATAL:
            return "FATAL";
        default:
            return "UNKNOWN";
        }
    }
    std::string GetTimeStamp()
    {
        time_t curr = time(nullptr);
        struct tm curr_tm;
        localtime_r(&curr, &curr_tm);
        char timebuffer[128];
        snprintf(timebuffer, sizeof(timebuffer),"%4d-%02d-%02d %02d:%02d:%02d",
            curr_tm.tm_year+1900,
            curr_tm.tm_mon+1,
            curr_tm.tm_mday,
            curr_tm.tm_hour,
            curr_tm.tm_min,
            curr_tm.tm_sec
        );
        return timebuffer;
    }

    class Logger
    {
    public:
        Logger()
        {
            EnableConsoleLogStrategy();
        }
        void EnableConsoleLogStrategy()
        {
            _fflush_strategy = std::make_unique<ConsoleLogStrategy>();
        }
        void EnableFileLogStrategy()
        {
            _fflush_strategy = std::make_unique<FileLogStrategy>();
        }

        // 一条日志
        class LogMessage
        {
        public:
            LogMessage(LogLevel &level, std::string &src_name, int line_number, Logger &logger)
                :_curr_time(GetTimeStamp())
                ,_level(level)
                ,_pid(getpid())
                ,_src_name(src_name)
                ,_line_number(line_number)
                ,_logger(logger)
            {
                std::stringstream ss;
                ss << "[" << _curr_time << "] "
                   << "[" << Level2Str(_level) << "] "
                   << "[" << _pid << "] "
                   << "[" << _src_name << "] "
                   << "[" << _line_number << "] "
                   << "- ";
                _loginfo = ss.str();
            }

            // LogMessage(...) << "hello world" << 1 << 3.14
            template <typename T>
            LogMessage &operator<<(const T &info)
            {
                std::stringstream ss;
                ss << info;
                _loginfo += ss.str();
                return *this;
            }

            ~LogMessage()
            {
                if (_logger._fflush_strategy)
                {
                    _logger._fflush_strategy->SyncLog(_loginfo);
                }
            }
        private:
            std::string _curr_time;
            LogLevel _level;
            pid_t _pid;
            std::string _src_name;
            int _line_number;
            std::string _loginfo; // 合并之后，一条完整的信息
            Logger &_logger;
        };

        // 返回临时对象
        LogMessage operator()(LogLevel level, std::string name, int line)
        {
            return LogMessage(level, name, line, *this);
        }
        ~Logger()
        {}
    private:
        std::unique_ptr<LogStrategy> _fflush_strategy;
    };

    // 全局日志对象
    Logger logger;

    // 使用宏，简化用户操作，获取文件名和行号
    #define LOG(level) logger(level, __FILE__, __LINE__)
    #define Enable_Console_Log_Strategy() logger.EnableConsoleLogStrategy()
    #define Enable_File_Log_Strategy() logger.EnableFileLogStrategy()
}

#endif